40. Structuring larger programs: packages and __init__.py — Python Theory

A directory containing an `__init__.py` (even an empty one) is a package, letting you organize related modules under a shared namespace.

python
# mypackage/__init__.py
from .wallet import Wallet
from .chain import ChainClient

# usage elsewhere:
from mypackage import Wallet

Relative imports (`from .module import name`) reference siblings within the same package; absolute imports reference the full dotted path from the project root. Since Python 3.3, "namespace packages" can technically omit `__init__.py`, but including it explicitly remains common for clarity and to control the package's public API via `__all__`.

40. Structuring larger programs: packages and init.py

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